On May 4, PlanetSolar--a boat powered solely by the sun--will complete its nearly two-year journey around the world. "It is not just a boat, it is a message," says expedition leader Raphael Domjan, who wanted to prove the viability of solar energy. More important, he learned some lessons for future explorers.
CHALLENGE: No how-to guide
The six-person crew was the first to attempt this journey on this kind of ship.
SOLUTION: Before hitting the water, the crew had to anticipate any and all potential problems. To do so, they utilized new software and used meteorological technology to predict winds and currents far in advance.
CHALLENGE: Variable sunlight
PlanetSolar was being fueled by a power source the crew had no control over.
SOLUTION: By mapping out the sun's projected conditions, the crew was able to plan ahead. It adapted the boat's route and speed to, when needed, efficiently use energy stored in the boat's six lithium-ion batteries.
CHALLENGE: Slow speeds
Because solar power is less potent than diesel, PlanetSolar traveled at just 5 knots rather than the typical 20, making the ship vulnerable to pirate attacks.
SOLUTION: A fence made it impossible to climb onto the boat, and armed guards stood watch. For safety at night, they traveled without any lights.